Recently two methods are available for the determination of environmental noise impact: model space calculation and on-site instrumental measurement. Both the correlations, constituting the basis of modelling and the structure of the instrument applied for measurement and the measuring requirements look back on a past of several decades. However, with the development of technology, the barriers mainly the information technological ones of noise impact determination have been eliminated one after the other. In regard of model calculations, noise mapping and in that of on-site measurement the appearance of real-time monitoring represented the breakthrough. The former opened the way to the graphic representation of the spatial distribution of the noise impact, whereas the latter has made it possible to produce a continuous time function being updated in real time. U.S. Pat. No. 7,092,853 discloses an environmental noise monitoring system which records and analyses environmental noise. The system is capable of sampling, processing and storing equivalent sound level values throughout a period of even two weeks. It is capable of showing the recorded data as chart and to detect automatically the indicated noise events subjected to observation. The measuring system conforms to IEC standards Type I or II. In the applied procedure, the detected noise is weighted by various frequency filters according to the national or international noise measurement standards; detected and weighted noise is converted into appropriate data, and data collection and processing is controlled through a communication interface, and then the values concerned are processed and displayed with the help of an analytical unit. The solution emphasises the filtering and compression of the detected values, and on the compliance of noise measurement with the various national and international standards and the provision of adequate results.
EP 1273927 A1 discloses a system and a method for environmental noise monitoring. The system comprises three or more sensor and converters, arranged in the environment comprising the noise source or noise sources at different places, and each sensor is omnidirectional. With the help of sensors located at different places, it can also delimit the direction of the noise sources with the help of sampled noise signal pairs, where it identifies by calculation the local maxima and determines the main noise source coming from a given direction, and detects noises coming from other directions and also their respective noise levels.
U.S. Pat. No. 7,266,494 discloses a method and an equipment identifying the noise environment from noise signals.
US 2010/0094625 A1 discloses methods and equipment for noise estimation. The solution is capable of detecting speech activity, taking into consideration the known differences between speech signals and the spectrum of ambient noise. The solution applies to noise detection in general.
A document entitled “Assessment of Environmental Noise Problems in Cluj-Napoca for an Appropriate Noise Management Plan” relates to environmental noise measurement. WO2011/045499 A1 discloses a method for the observation, estimation and reduction of the acoustic energy level of noise sources in aquatic environments, e.g. in lakes and seas, where a noise transmission source, e.g. a ship, is present in the aquatic environment. According to the method, the acoustic propagation of the noise source is modelled in real time, and the momentary position of the noise transmission source is determined from a database and when that is known, the desired parameters of the noise waves propagating in space from the noise transmission source are determined.
US 2010/0280826 A1 relates to the separation and monitoring of noise sources, and solves partly the issue of the determination of the location of the bundle reflected from the noise source and partly the filtering out of the noises associated with the original noise signals primarily through the useapplication of electromagnetic radiation, e.g. of laser beams. The applied beams let the respective noise sources be separated from one another completely.
US 2008/0056506 A1 discloses a structural noise source forecasting method to estimate the place and approximate measure of noises created after implementation already in the planning phase. The method covers also noise calculation.
Pages 2427-2443 of Issue 13, Vol. 14 of the periodical International Journal of Remote Sensing presents a regional noise estimation and management system comprising remote sensing and capable of providing information on the propagation of noise.
JP 2003156388 A relates to a method and an equipment for the detection of environmental noises and a data storage medium. During the solution, noise data are collected from a region regarded as several independent noise sources, and environmental noises are also taken into account. The solution refers primarily to the measurement and monitoring of noise indoors and in particular in buildings.
JP 2005190177 A discloses a system monitoring environmental noise effects, which can be applied e.g. also on construction sites where the noise sources may be noises created at certain decisive places/equipment of the construction works. The measured data are collected and forwarded via a communication network to an evaluation centre which carries out the evaluation of the parameters being sought based on the noise and vibration measurements.
EP 1 720 129 A1 discloses a method for studying and eliminating environmental noise pollutions, which measures the noises being produced at several locations, and determine by calculation from the noise map the actions required to eliminate them. The document demonstrates the existence of the problems related to noise impact.